The present invention relates to an arrangement for sealingly and detachably connecting the associated ends of the consecutive sections of an air conduit used in a vacuum cleaning device in general, and more particularly to such an arrangement for use for connecting an attachment to the vacuum cleaning device.
There have been already proposed various connecting arrangements of the type here under consideration, in many of which resort has been had to associated connecting sleeves one of which embraces the other in the assembled condition. To maintain the connecting sleeves in their assembled condition until disassembly, it has also already been proposed to provide the connecting sleeves with an arresting arrangement which, upon insertion of the inner one of the connecting sleeves into the outer one, arrests the inner sleeve in its inserted position. So, for instance, it has already been proposed to construct the arresting arrangement as a yieldable biased arresting member which is mounted on one of the connecting sleeves and which engages in a depression or the like of the other connecting sleeve in the assembled condition, to hold the connecting sleeve against axial displacement relative to one another until the arresting member is withdrawn from the depression.
Inasmuch as the connecting sleeves connect different sections of an air conduit, such as of a suction conduit, it is further required that the connecting arrangement consisting of the two associated connecting sleeves be gas-tight to the maximum feasible extent, that is, that it virtually eliminate any possibility of flow of gases through the interface between the connecting sleeves between the exterior and the interior of the conduit. To assure such gas-tightness, it has been already proposed to give both connecting sleeves slight conicities so that the inner connecting sleeve can be introduced into the interior of the outer connecting sleeve to such an extent until the conical inner and outer surfaces of the two connecting sleeves sealingly contact one another.
In such arrangements, it is quite disadvantageous that the dimensions of the connecting sleeves must be made to exact specifications, with only minimum tolerances. Were it otherwise, it would be possible that, when the inner connecting sleeve is fully inserted into the outer connecting sleeve to establish sealing contact therewith, the arresting member would be out of registry with the associated depression and thus could not engage therein. On the other hand, the other possibility, which is equally disadvantageous, would be that the arresting member would engage in the associated depression before the inner connecting sleeve has been fully inserted into the outer connecting sleeve. Under these circumstances, the conical surfaces of the two connecting sleeves would be out of, or only in an insufficient, contact with one another so that the path inbetween the two connecting sleeves which communicates the exterior with the interior of the conduit would be only insufficiently obstructed and, hence, air will be permitted to penetrate through the interspace between the two conical surfaces when the arresting member arrests the two sleeves in their arrested position. Furthermore, when torque is applied to the connection about the common axis of the connecting sleeves, the only force opposing rotation of the connecting sleeves relative to one another is that with which the arresting member abuts against the wall bounding the depression so that, given sufficient torque, the arresting member either is displaced out of the depression, thus terminating the arresting action thereof, or is destroyed or damaged when the force acting thereon exceeds a certain value. Thus, it will be appreciated from the above explanation that, in the above-discussed conventional arrangement, a connection which satisfies all the requirements can only be achieved when the two associated connecting sleeves and the associated parts are manufactured with a high degree of precision.